Cost-effectiveness of Intensive vs Standard Blood Pressure Control Among Older Patients With Hypertension

Key Points Question Is intensive blood pressure management among older patients with hypertension cost-effective? Findings This economic evaluation with a Markov model and extensive sensitivity analyses estimated the incremental lifetime medical costs, quality-adjusted life-years (QALYs), and cost-effectiveness of intensive vs standard blood pressure targets for older patients with hypertension in China, the US, and the UK. Intensive blood pressure control produced fewer cardiovascular events and low costs per QALY gained, well below the typical willingness-to-pay thresholds, and the cost-effective advantages were consistent over various clinical scenarios across different countries. Meaning These clinical and economic findings suggest intensive blood pressure control is cost-effective in older adults.

the yearly risks to the lifelong period based on the obtained estimates. In the sensitivity analyses, we tested the scenarios with simulation to only 84 years in the China-PAR model and 79 years in the AHA/ACC Pooled Cohort Equation to assess the uncertainty resulting from the extrapolation methods. Besides, although these three models were used in the post-trial period to simulate the different treatment effects, the individual CVD events of the models did not perfectly match the STEP trial. Therefore, we used further scenario analyses with different risk ranges in the model to assess the ICER values.

Adherence
Adherence is crucial for reaching the target in blood-pressure management. In this model, the percentage of the blood pressure reaching the target was assumed to reflect treatment adherence. Patients in the intensive treatment group who did not adhere to their medications reverted to either their baseline, pretrial systolic blood pressure (major) or the standard treatment targets (minor). Those in the standard treatment group all reverted to their baseline. The CVD risk assessment models were used to estimate the treatment effects according to the SBP and other characteristics.
The meta-analysis of M. Iskedjian et al. 2002 showed that the more medications, the lower adherence. The mean numbers of medications in the STEP trial were 1.9 and 1.5 in the intensive and standard groups, and the percentage of blood pressure reaching the target was 76% in both groups at the end of the trial. Therefore, for the base-case analyses, adherence to intensive and standard treatments was assumed to be 70% and 75% based on the target-reaching percentages and the number of antihypertensive medications. In the worst-case scenario, patients in the intensive group were assumed to be non-adherent (0%) to antihypertensive medications immediately after the trial. In contrast, the standard group had perfect adherence (100%) and obtained the treatment effects. Regarding the best-case scenario, the patients in the intensive group adhered to all medications (100%), and the standard group adhered to medications as in the base case. Different adherence changes with time were considered in the scenario analyses.

Costs
Medical costs came from the published data. We inflated the costs by 3% annually to 2022. If the costs of non-cardiovascular death and cardiovascular death were lacking, cardiovascular events were pooled to estimate the costs of cardiovascular death, and we assumed equal costs for cardiovascular and non-cardiovascular death. We used the purchasing power parity currency instead of the nominal exchange rate to compare the costs between the three countries. The currency was compared between China vs the U.S. (¥4.18=$1) and the U.K. vs the U.S. (£0.688 = $1)

Assumption for repeated cardiovascular events
This model used a Markov model, allowing the simulated individuals to move to the subsequent clinical events according to the given probabilities in each cycle. The probability for the second event would be multiplied by the estimates. For example, the probability of the individual who experienced a stroke (the previous cycle) and then acute heart failure (this cycle) can be obtained by multiplying the probability of stroke and acute heart failure. Usually, repeated CVD risks are higher than the firsttime CVD risk. This model assumed that the repeated CVD risks were consistent with the first-time risks, and higher risks for the repeated CVD events were considered in the scenario analyses. The medical costs for this individual in this cycle included baseline healthcare, anti-hypertensive treatments, chronic stroke and acute heart failure. The acute stroke happened in the previous cycle, so the costs were not included in this cycle. The utilities in this cycle were calculated, i.e., (utilityhypertension*utility multiplierpost_stroke-disutilityage)-(disutilityacute_heart_failure).
Besides, the costs and utilities were discounted by the given discount rate annually.
Finally, lifetime medical costs were calculated by multiplying the number of subjects by the sum of the costs of each health status. Total QALYs were accumulated from the QALY in each cycle, obtained from the utility values associated with each health status multiplied by the proportion of subjects living in that status. -PAR risk model provides 10-years cardiovascular risks for people aged younger than 85 years. The yearly risk for those aged more than 85 years was extrapolated by the function based on the yearly risk from 66 to 85 years (grey column).
The risks were calculated from the risk of males and females according to the sample percentage in the STEP trial.